MRAM is a nonvolatile memory technology that uses magnetic polarization to store data, in contrast to other RAM technologies that use electronic charges to store data. One primary benefit of MRAM is that it retains the stored data in the absence of applied system power, thus, it is a nonvolatile memory. Generally, MRAM includes a large number of magnetic cells formed on a semiconductor substrate, where each cell represents one data bit. Information is written to a cell by changing the magnetization direction of the magnetic free layer within the cell, and a bit is read by measuring the resistance of the cell (low resistance typically represents a “0” bit and high resistance typically represents a “1” bit).
An MRAM device generally includes an array of cells that are interconnected using conductive bit lines, conductive digit lines, and/or local interconnects and the like. Practical MRAM devices are fabricated using known semiconductor process technologies. For example, the bit and digit lines are formed from different metal layers, which are separated by one or more insulating and/or additional metal layers. Conventional fabrication processes allow distinct MRAM devices to be easily fabricated on a devoted substrate.
Smart power integrated circuits are single-chip devices capable of generating and providing operating power in a controlled and intelligent manner. Smart power integrated circuits typically include a power circuit component, an analog control component, and a digital logic component. Smart power integrated circuits may also include one or more sensors which can be used to measure or detect physical parameters such as position, motion, force, acceleration, temperature, pressure and so forth. Such sensors can be used, for example, to control the output power in response to changing operating conditions. For example, in cell phones, smart power products can be engineered to regulate power consumption, amplify audio signals, and supply power to color screens. In inkjet printers, smart power products can help drive the motors and fire the nozzles for ink delivery. In automobiles, smart power products can help control engine and braking systems, airbag deployments, and seat positioning.
For integrated circuits (IC's) which implement smart power and magnetic random access memory (MRAM) designs, current sensing is an important element of power IC design to protect the circuit, device or system.
Existing sensors for measuring parameters such as those mentioned above suffer from various limitations well known in the art. Examples of such limitations include excessive size and weight, inadequate sensitivity and/or dynamic range, cost, reliability and other factors. Thus, there continues to be a need for improved sensors, especially sensors that can be easily integrated with semiconductor devices and integrated circuits and manufacturing methods therefore.
The miniaturization of many modem applications make it desirable to shrink the physical size of electronic devices, integrate multiple components or devices into a single chip, and/or improve circuit layout efficiency. Ideally, such sensors should be manufactured in a cost effective manner which reduces the additional layout area or space the sensors consumes. It would be desirable to have a semiconductor-based device which includes an MRAM architecture integrated with a smart power architecture including sensor components on a single substrate, particularly where the MRAM architecture and the smart power architecture are fabricated using the same process technology such that the sensor is compatible with semiconductor device and integrated circuit structures and fabrication methods.
Accordingly, it is desirable to provide an improved sensor and method, adaptable for measuring various physical parameters. It is further desirable that the improved sensor and method convert the physical parameter being measured into an electrical signal. It would be desirable to provide sensors which exhibit improved measurement performance and which can be integrated in a three-dimensional architecture. Other desirable features and characteristics of the invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.